Get first number of type CGFloat - swift

Question

I have following numbers in CGFloat
375.0
637.0
995.0
I need to get the first number in CGFloat data type. For example the result for #1 must be 3.0, for #2 must be 6.0 and #3 must be 9.0
I tried the following
let width:CGFloat = 375.0
// Convert Float To String
let widthInStringFormat = String(describing: width)
// Get First Character Of The String
let firstCharacter = widthInStringFormat.first
// Convert Character To String
let firstCharacterInStringFormat = String(describing: firstCharacter)
// Convert String To CGFloat
//let firstCharacterInFloat = (firstCharacter as NSString).floatValue
//let firstCharacterInFloat = CGFloat(firstCharacter)
//let firstCharacterInFloat = NumberFormatter().number(from: firstCharacter)
Nothing seems working here. Where am I going wrong?
Update
To answer #Martin R, find below my explanation
I am implementing a grid-view (like photos app) using UICollectionView. I want the cells to be resized based on screen size for iPhone/iPad, Portrait and Landscape. Basically I don't want fixed columns. I need more columns for larger screen sizes and lesser column for smaller screen sizes. I figured that perhaps I can decide based on screen width. For example if the screen width is 375.0 then display 3 columns, If somewhere around 600 then display 6 columns, if around 1000 then display 10 columns and so on with equal width. So what I came up with is a) decide columns based on first number of the screen size and then for width divide by actual screen width. For example for a screen width of 375.0 I will have a cell size of CGSize(width: screenWidth / totalColumn) and so on.

Answer 1

You said:
For example if the screen width is 375.0 then display 3 columns, If somewhere around 600 then display 6 columns, if around 1000 then display 10 columns and so on with equal width.
So what you really want is not the first digit of the width (which would
for example be 1 for width = 1024 instead of the desired 10)
but the width divided by 100 and rounded down to the next integral value:
let numColumns = (width / 100.0).rounded(.down)
Or, as an integer value:
let numColumns = Int(width / 100.0)

Answer 2

var floatNum:CGFloat = 764.34
var numberNeg = false
if floatNum < 0{
floatNum = -1.0 * floatNum
numberNeg = true
}
var intNum = Int(floatNum)
print(intNum) //764
while (intNum>9) {
intNum = Int(intNum/10)
}
floatNum = CGFloat(intNum)
if numberNeg {
floatNum = -1.0 * floatNum
}
print(intNum)//7
print(floatNum)//7.0
try this one ...I hope it'll work